Nettle-feeding nymphalid butterflies: temperature, development and distribution

1. Four nymphalid butterflies, Aglais urticae L., Inachis io L., Polygonia c-album L. and Vanessa atalanta L., share the same primary host plant, Urtica dioica L., but have different margins to their U.K. and European ranges. Their developmental responses to a series of constant temperatures were measured.
2. Degree-day requirements were found broadly to explain the relative distributions and differences in voltinism of A. urticae , P. c-album and I. io . The migrant V. atalanta did not fit into the predicted pattern, and this species may be more limited by its ability to overwinter.
3. Although the most northerly distributed species, A. urticae , had the lowest degree-day requirement, it had the highest developmental threshold and performed best (for mortality, pupal weight and relative growth rate) at high experimental temperatures. It is suggested that this may be due to the gregarious nature of its larvae and their possible ability to thermoregulate.
4. At southern margins, different distributional limits may be explained partly by larval gregariousness (a more northern trait) and maximum temperatures at which development is possible.
5. Limits to the distributions of these mobile species are at least partially explicable by the interaction of climatic patterns and thermal biology. A rapid response to climate change is predicted, and has already been observed in two of the species.     

Ultrastructure of the Parabasalid Protist Holomastigotoides

ABSTRACT. The ultrastructure of two species of Holomastigotoides is presented. The basic unit of organization of these large cells is the flagellar band. Each flagellar band consists of a row of flagellar basal bodies linked by three fiber systems. The number of flagellar bands is species dependent. The flagellar bands originate at the cell apex and are arranged in parallel spirals of increasing gyre, thus defining the conical shape of the cell. In the cell apex a striated root called a parabasal fiber is juxtaposed with the basal bodies of each flagellar band. Linear extensions of two parabasal fibers function as the spindle poles for the persistent extra-nuclear spindle. The nucleus is in close contact with the spindle poles and spindle microtubules. Parallel sheets of microtubules which constitute axostyles are nucleated along the underside of the parabasal fibers. The axostyles extend away from the cell apex, with many reaching the basal region of the cell. Some of the axostyles follow the spiral pattern of the flagellar bands. Numerous Golgi bodies are spaced regularly along the flagellar bands. Together the parabasal fiber, axostyles and Golgi bodies associated with a flagellar band are termed a parabasal complex.     

Protein hydrolysates and associated bacterial contaminants as oviposition attractants for the mosquito Culex quinquefasciatus

Abstract. Six protein or protein hydrolysate solutions were tested for activity as attractants for ovipositing Culex quinquefasciatus mosquitoes in the laboratory. Four of these solutions (egg albumin, lactalbumin hydrolysate, casein hydrolysate and yeast hydrolysate) were attractive to ovipositing females at varying concentrations, when compared to distilled water controls. Soy hydrolysate was repellent at 1%, but not significantly attractive or repellent at lower concentrations. 'Nulure', a tephritid fly bait containing protein hydrolysate, also had no significant effect on oviposition behaviour. Gravid females mostly oviposited within the first 4 h of the scotophase, regardless of the presence or absence of an oviposition attractant.
Lactalbumin hydrolysate 1% solution, with or without 0.1% neomycin antibiotic, was attractive to Cx quinquefasciatus . This effect was reduced by the presence of neomycin which, alone, had no effect on oviposition. Hence both lactalbumin hydrolysate and bacterial contaminants were shown to be attractive to gravid Cx quinquefasciatus .